1. Field of the Invention
This invention relates to a method of and an apparatus for measuring and adjusting the wheel alignment of automotive vehicles.
2. Prior Art
Wheel alignment of four-wheeled automotive vehicles such as passenger cars, buses and trucks is effected conventionally with all of the four wheels mounted on respective rotary drums in a wheel alignment testing apparatus and rotated at a predetermined rate of speed, whereupon the toe-in or camber of each wheel is checked and adjusted to the manufacturer's specifications. In such instance, it is essential to see to it that the wheels are mounted on the respective drums with the center line of the vehicle axle registered with the longitudinal center line of the testing apparatus. Failing this would result in misaligned wheels and hence defective drive performance.
A prior art approach has been proposed in which a pair of oppositely disposed limiter arms are used to restrict lateral shift or displacement of each of the front and rear wheels in a direction transverse to the center line of the testing apparatus after the vehicle is mounted and brought into center-to-center registry with the apparatus. This approach however has a drawback firstly in that it is cumbersome and time-consuming to guide the vehicle as by an equalizer into proper registration with the testing apparatus and secondly in that because of coercive positioning the wheels against inherent axial movement with respect to the rotary drums, undue stress is imposed on the wheels which would hinder accurate measurement of wheel alignment approximating actual on-road performance.